Does Global Climate Change Have Natural Causes?

Does Global Climate Change Have Natural Causes?

Article excerpt

An Interview with Kenneth L. Verosub, Ph.D.

Q: What is global warming?

A: Many people do not even like the term "global warming"; they like "global climate change," meaning that the climate is changing. Some of the effects' suggest that the world is getting warmer, ice sheets are melting, and water in the ocean is heating up. As it heats up, it makes the sea level rise. All of these events together can be considered global climate change.

All of these changes will have an impact. For example, a large percentage of people live at or near sea level; those people would be forced to move or relocate. As the climate changes," crops are going to be grown differently or what we grow in different places is going to change.

It is certainly possible that tropical diseases, such as malaria, would increase. As the air warm up, insects that carry particular diseases would be able to move and bring those diseases with them. Some epidemics that have been more or less confined to Africa would move north into southern Europe. In addition, with as much airline traffic as we have now, organisms that can bring disease are potential threats to plants, animals, and humans. All kinds of plants and animal or tropical diseases might well be able to move into new areas.

Q: Is it warmer today than in the 1930's, for example?

A: The global rise in temperature is only a few tenths of a degree. Although the total net change is small, the effect can be huge, such as trees blooming early and birds being out of sync with the insects that they feed on. One of the biggest problems is the rising temperature of the ocean. It's a big ocean; if you heat the ocean just a few tenths of a degree and it expands, the only way the ocean can go is up, because it has a side and it has a bottom. As the ocean heats up and starts to expand, even though it's just a small temperature change, when that change occurs over thousands of meters of water depth, it raises the high of the water by a measurable amount.

In some places, this change is on the order of 10 or 15 centimeters. There is an island in the Pacific Ocean where the residents were right at sea level and now they are under water most of the time. The ocean is slowly rising and is going to erode. Storms will be able to come in a little farther and erode more of the sand. Basically, there are cycles of changes; however, we are now seeing warmer temperatures than at any time in the last 1 ,000 years or maybe 1 0,000 years. Experts agree that the world is warmer now than it had been 50 or 100 years ago.

Q: What are greenhouse gases?

A: A greenhouse gas absorbs visibleTadiation (sunlight) and emits it as heat. The main greenhouse gas is carbon dioxide (CO2). Water vapor is also a greenhouse gas. As you increase the amount of CO2 in the atmosphere, the sunlight hits the earth. Some of this would normally reflect back into space, but because of the CO2, the reflective sunlight is absorbed by the CO2. It is then readmitted as heat, which then does not go back into space. It is the same principle as a greenhouse.

In a greenhouse, sunlight shines through glass and is converted into heat. Because the glass does not transmit the heat, the heat is trapped. This is why a greenhouse gets hot.

Q: Are carbon and greenhouse gases necessary for the existence of life as we know it?

A: We are carbon-based life, so carbon is important. CO2 is important, because it drives photosynthesis.

Q: How do volcanoes cause climate changes?

A: There is a specific mechanism for that. If a large volcanic eruption has a lot of sulfur dioxide (SO^sub 2^) in the gas, the SO^sub 2^ gets injected into the upper atmosphere, where it combines with water (H2O). and we get little droplets of sulfuric acid (H^sub 2^SO^sub 4^). We literally get a veil of these H^sub 2^SO^sub 4^ droplets all around the earth, and they reflect some of the sunlight enough to cool the earth. …